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LM35 and TL431 Automatic Temperature Control

Electronic Project circuit - Automatic Temperature Control
This is an electronic circuit that can be used as automatic temperature control aapplication. The circuit switches a miniature relay ON or OFF according to the temperature detected by the one-chip temperature sensor LM35. When the LM35 detects a temperature higher than the preset level (set by VR1), the relay is actuated. When the temperature falls below the preset temperature, relay is de-energized. The circuit can be powered by any AC or DC 12V supply or battery (100mA min.)

Download : schematic, layout and PCB (pdf)

related search : Electronic circuit project, automatic application, temperauter controller, LM 35 (src)





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8 Comentar:

Anonymous said...

What is IC3?
Diode value?
what is temperature range circuit can manage?
What is relay rating?

I want to use this circuit to control 50W 220V heater. But I want this circuit to ON the heater once its fall below preset level and and OFF when it reach equal or little above the preset level. Can it do that?

Please help.

admin said...

What is IC3? IC3 : LM358 Dual single supply Op-amp.

Diode value? D1, D2 -- 1N4148 silicon diodes (or 1SS133)
D3, D4 -- 1N400x (x=2,,,,.7) rectifier diodes

what is temperature range circuit can manage? 0 ~ 150oC (cek lm35 datasheet)

What is relay rating? Miniature relay -- DC12V DPDT, Coil=400 O or higher

I want to use this circuit to control 50W 220V heater. But I want this circuit to ON the heater once its fall below preset level and and OFF when it reach equal or little above the preset level. Can it do that? yes it can.

When the LM35 detects a temperature higher than the preset level (set by VR1), the relay is actuated. When the temperature falls below the preset temperature, relay is de-energized. The circuit can be powered by any AC or DC 12V supply or battery (100mA min.)

Anonymous said...

if i'm not wrong..the lm358(IC3) need to be programmed first before the circuit can work..am i right?

so..can i have a look on the coding for IC3? it may help a little bit for my project..tq =)

admin said...

No, LM 35 is temperature sensor and no need to be programmed

bruno mozzi said...

hello, cool your post-!.. ? i need the value of components, resistors, capacitors and more, thank you

Anonymous said...

no..i mean..

the IC3 : LM 358 - dual single supply op-amp..

it is a microcontroller..right?..or it is just a normal op-amp??..which no need to be programmed?

admin said...

^ LM 358 is dual single supply op-amp. so it no need programmed. This project actually use op-amp as comparator (see: schematic) and it doesn't need microcontroller.

admin said...

@bruno

IC1 : LM35DZ Precision Celsius (Centigrade) Temperature sensor
IC2 : TL431 +2.5V precision voltage reference
IC3 : LM358 Dual single supply Op-amp.

LED1 -- 3mm or 5mm LED

Q1 -- General purpose PNP transistor ( A1015,...) with E-C-B pin-out)

D1, D2 -- 1N4148 silicon diodes (or 1SS133)
D3, D4 -- 1N400x (x=2,,,,.7) rectifier diodes

ZD1 --- Zener diode, 13V, 400mW

Preset (trim pot) : 2.2K (Temperature set point) (# 222 or 2k2)

Resistor : ( 1/4W or 1/6W)

* R1 -- 10K
* R2 -- 4.7M
* R3 -- 1.2K
* R4 -- 1K
* R5 -- 1K
* R6 -- 33Ω

Capacitors :

* C1 -- 0.1 µF ceramic or mylar cap
(# 104 or 100n)
* C2 -- 470 µF or 680 µF electrolytic cap.
(16V min)

Miscellaneous items :
8-pin socket -- x 1 pcs
Miniature relay -- DC12V DPDT, Coil=400 Ω or higher

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